Double-threaded screw



Dec. 6, 1927.

J. A. ARENZ DOUBLE THREADED SCREW Filed March 2, 1925 Patented Dec. 6, 192?.

carries mm earner series.

JOHN A. ARENZ, OF CHICAGO, ILLINOIS, ASSIGNOR TO INTERNATIONAL SCREW COM- IPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

DOUBLE-THREADED scnnw.

Application filed. March 2, 1925.

My invention relates to screws having particular reference to'a wood screw f'th-e type used by carpenters, tradesmen and the like, and which is adapted to be turned into position by means of a screw driver or the like.

The primary object of my invention is the provision of a screw having a tapered body portion with a double thread upon the body 1 portion of the screw, the said double thread terminating in a single penetrating point so that the screw will enter and separate the fibers of the wood into which the screw is driven rather than out the fibers from the wood as is common with screws of this type heretofore manufactured.

I am aware that screws of the same general type as my improvements have been used heretofore, but these screws have a pair of incising blades at the end of the screw, each thread terminating in an incising blade and which cut the fibers of'the wood as the screw is driven into the wood, and which cut out the fibers of the wood at least to the diameter of the two incising blades and thereafter the fibers are spread somewhat and engaged by the threads on the side of the screw. The common ordinary type of commercial screw has a single thread which terminates in a point, but this point is not an incising one and in driving this screw into wood a glmlet hole must be made, particularly if the wood is hard, before the screw can be driven into the wood at all.

Another object of my invention is the provision of a double threaded screw, having the threads fashioned into a single penetrating point and which has the thread formed thereon having a longer angle at the upper side of the thread'than at the under side thereby enabling the screw to force its way into wood easier than the ordinary screw and with less force needed to drive it into position. 1

Another and further object of my invention is the provision of a screw which can be easily and cheaply manufactured and which has an incising or chiseled int thereon which enables it to be driven into the wood in a straitght line without the danger of breaking e point which sometimes occurs detail,

Serial No. 12,547.

with a double point screw of the type above described and resulting in the screw traveling at an angle into the wood, which also occurs when the two points of the double threaded screw are not exactly even.

These and other objects of my invention are more fully described and better understood by referring to the accompanying sheet of drawings in which Figure 1 is a side elevational view of the screw embodying my invention, and

Figure 2 is a diagrammatic View, showing the outlines of the threads in an enlarged form converging to cutting edges tapering to a point.

Figure 3 is a side elevational view of the screw, shown at right angles to the illustration in Figure 1.

Referring now specifically to the drawings and in which like reference characters refer to like parts throughout, a screw 10 is shown having a head 11 secured thereto with transversely extending slot 12 therein so that the head may be engaged by a screw driver or the like. The screw 10 is formed with the stem 13 having a tapered portion 14 terminating in a central penetrating point 17, and the double threads 15 and 16, slightly undercut, and extending from said stem 1nto and along the tapered portion 14 thereof and finishing on either side of the point 17 and merging into the cutters 18 and 19, which converge to said point across the grooves or channels 20 and 21 of the threads respectively.

The operation of the device is exceedingly simple there being no necessity for making a gimlet hole or an incision into the wood as there is with either a sin le thread screw or a double thread screw wit two points, unless the wood is exceedingly hard, and for this reason the screw also is much easier secured in place than screws of this type which have heretofdre been manufactured, and hold in position very much better than an ordinary screw or the double threaded two point screw.

Though a preferred embodiment of the present invention has been described in it will be clear that many modifications will occur to those skilled in the art.-

; It is intended to cover all such modifications merged to form a sharp point and forming that fall within the scope of the appended. oppositely positioned cutting edges extendclaim. ing from said point to initially open the What is claimed is: work to the path of the screw in penetrating 5 A screw comprisin 'a stem and tapered operations.

point having a plurality of threads spirally Signed at Chicago, Illinois, this 21st day extending to the extreme ti of the ta ered of February, 1925. portion, the ends of sai spirals ing JOHN A; ARENZ. 

